Trailer Requirements in WA

Does anyone know or know where I can out if I can bring an unlicensed trailer from Oregon (not required to be licensed in Oregon) into WA or if I'd need a trip permit?  I found some stuff on the DMV site which states that all trailers in WA are required to have license plates but haven't found anything yet about out of state trailers in transit.

http://www.wsp.wa.gov/traveler/docs/cvd/170_129.pdf

On hold with the DMV, they didn't know either.

On to the WSP, DMV had no answer.

Your trailer is being towed by your Oregon licensed vehicle, therefore follows Oregon DMV rules, not Washington DMV.

In Oregon trailers under 1500 lbs (or was it 1800) are not required to be licensed.

Nobody has ever harassed me with my trailer in the 21 states I've towed it through.

You're good!

Thanks, Insayn.  Same conclusion the WSP came to regarding it.  Just wanted to double check before I got a fine.  Looked into the OR fees for registering (not required for under 1800 lbs as you said) and its the same as a passenger car so definitely not going that route, either.

Happy towing!!!